Triggered standard signal generator



Oct. 23, 1956 B'. M. GORDON TNIDQERED STANDARD SIGNAL GENERATOR- F'led June 16, 1951 MAH .A A R, bw.

INVENTOR.

BERNARD M. GORDON ATTORN Y United States Patent O TRIGGERED STANDARD SIGNAL GENERATOR Bernard M. Gordon, Philadelphia, Pa., assignor, by mesne assignments, to Sperry Rand Corporation, New York, N. Y., a corporation of Delaware `Applicant@ June 16, 19511, serial No. 232,022

1o claims. (ci. 25o-,27)

This invention relates to signalling apparatus, and more particularly, to apparatus of this type in which a signal of standard character is emitted under the control of stimuli appearing in an information channel.

Recent years have witnessed a considerable effort in the application of pulse techniques to the transmission of intelligence. These techniques have included the transmission of such intelligence by the use of pulse time modulation, pulse amplitude modulation, and pulse code modulation, to cite a few examples. In the latter type of transmission, the nature of the information being transmitted is used to control pulse code groups. It has been found that the amount of information which may be transmitted over a channel of given band width, using pulse notation, is doubled by the use of the pulse envelope system, as distinguished from the return to zero system of transmission. It has also been found that in many applications, it is desirable to use wave packets in place of essentially flat-topped pulses. If a gated carrier is used in generating the wave packet, it is important, to the successful operation of the pulse envelope system, that successive packets merge to provide a resultant continuous function, free of discontinuities. There are also times when it is desirable to convert information present in discrete pulse form into the pulse envelope notation. Many of` these problems are encountered in the conversion of information in the form of pulse trains into wave packets incidental to the storage of such information in the recirculating type of memory system found in large scale digital computers. Such a computer has been described in copending application Serial No. 279,710 entitled lnformation Handling System and filed in the names of I. P. Eckert et al.

Accordingly, it is a primary object of the invention to provide new and novel signalling apparatus for converting information impulses whose timing may have been undesirably altered, into standard signals fitting precisely into a desired timed frame.

Another object of the invention is to provide new and novel apparatus for converting information in the discrete pulse system to information in the pulse envelope system of notation.

A further object of the invent-ion is to provide new and novel apparatus delivering output in the pulse envelope system, characterized by the used of wave packets.

Still another object of the invention is to provide a keyed standard timed wave packet generator with a minimum number of components and cooperating electric valves.

Other objects and advantages of the invention will in part be discussed and in part be obvious as the following specification is read in conjunction with:

The single ligure drawing schematically illustrating apparatus displaying the principles of the invention.

While thermionic tubes have been used in the illustrative .Sample disclosing. the Principles f. the, invention.,

. 56, which may be connected with ground, and within.

ICC

the drawing has been simplilied by the omission of the heater circuits normally associated with such devices and the detailed power supplies therefor. The references to operating potentials have been standardized in the following manner:

Each power supply bus is designated by a reference character whose value is equal to the magnitude of the voltage concerned. Positive voltages are indicated by even-numbered reference characters, while negative voltages are indicated by odd-numbered reference characters. Power supply leads may be provided with the decoupling and liltering circuits familiar in current engineering practice. Component values, operating potentials, and specic tube types, are mentioned by way of example only, to assist in understanding the application of the invention in a particular form. They may, of course, be varied to meet the specific requirements of various applications.

The electric impulses governing the operation of the apparatus are applied to a signal input lead terminating at the connector 10 coupled through capacitor 11 and parasitic suppressing resistor 12, which may be about 2,000 ohms, to the control grid 13 of an. input tube 14 which may be of the type commercially designated 25L6. The input tube 14 has a cathode 17 returned to the negative supply bus 61, and a diode 16 is bridged between the control grid 13 and the cathode 17, the anode of diode 16 being connected with the said control grid 13 and the cathode of the diode 16 being connected with cathode 17. A grid return is provided by the resistor 19, which may be about 100,000 ohms, bridged between the grid side of capacitor 11 and ground. The anode 21 of the tube14 may be fed from the positive supply bus 20 through a resistor 22 of about 820 ohms, and the space charge grid 23 of the tube 14 is connected with ground. A diode 30 has its cathode connected with the anode 21 and its anode returned to the negative supply bus 15, while a second diode 31 has its anode `connected with the anode 21 of the tube 14 and its cathode connected with ground. The diodes 30 and 31 serve as clamping or voltage excursion limiting diodes restraining the potential variations of the anode 21 within predetermined limits.

Signals appearing at the anode 21 of the tube 14 are fed to the anode of a diode 33, whose cathode is joined at the junction 36 to the resistor 34, which may be about 18,000 ohms, returned to the negative supply bus 217. The anode of a further diode 32 is also fed from the anode 21 of the tube 14. The cathode of the diode 32 is connected at junction 50 with the anode of an additional diode 35 whose cathode is joined to the cathode of diode 33. The junction point 36 may be fed from the movable tap on potentiometer 38 through diode 37 whose cathode is connected to the junction 36. The anode of diode 37 is connected with the movable tapon the potentiometer 38 whose resistive element is excited by negative-going impulses applied to an input terminal 39 coupled by capacitor 40 to the ungrounded side of potentiometer 38. The impulses applied to the terminal 39 may be derived from any suitable source and have a duration of approximately .06 microsecond and a period The junction point 50 is coupled with the outer con,n

trol grid 51 of the tube 52, which may be of the type commercially designated 7AK7, through a parasitic suppressing resistor 53, and is returned to the negative supply bus 217 through a resistor S4 which may be about 27,000 ohms. The tube 52 is provided with a cathode space charge grid S8 returned to the positive supply bus 106. The inner control grid 55, located between the space charge grid 58 and the cathode 56, is connected through a parasitic suppressing resistor 60 with the cathode of a diode 61 whose anode may be connected with the movable tap of potentiometer 62. One end of the potentiometer 62 is returned to the negative supply bus 25, while the other end of the resistive element is coupled through a capacitor 63 with a source of positivegoing impulses occurring substantially simultaneously with the negative-going impulses` supplied to the terminal 39. The impulses at the terminal 64 may, as before, be above .06 microsecond wide with a period of about 0.45 microsecond. These impulses proceed 38 volts positively from a negative 88-volt reference potential. The information'transmitting signals applied to the signal input terminal 10 are entirely independent from and unrelated to the substantially synchronized negative and positive clock pulses received at the input terminals 39 and 64, respectively. The cathode of the diode 61 is returned to the negative supply bus 217 through a resistor 59 which may be about 27,000 ohms.

The anode 57 of the tube 52 may be connected with the positive supply bus 200 through a resistor 65 of about 5,000 ohms and an inductance 66 of about 150 microhenries. The anode of the tube 52 is further connected with the anode of a diode 67 whose cathode is fed from the positive supply bus 130, and to the cathode of a diode 63 whose anode is linked to the positive supply bus 90. A parallel resistance-capacitance network 70 connects the outer control grid 51 of the tube 52 with the space charge grid 71 of the tube 72. The said space charge grid 71 may also be connected with the inner control grid 55 of the tube 52 by similar parallel resistance and capacitor network 75. The resistance in each of the networks 70, 75 may be about 15,000 ohms, while the capacitor may have any suitable value, usually in the range of 5 to 50 mmfd. The line from the anode 57 of the tube 52 is connected with the inner control grid 76 of the tube 72 through a resistance of about 15,000 ohms Shunted by a capacitor between 5 and 50 mmfd. A negative return for the inner control grid 76 of the tube 72 is provided by a resistor 83 of about 27,000 ohms returned to the negative supply bus 217 and the usual parasitic suppressing resistor 84 is connected in the lead to the said inner control grid 76. A positive potential is supplied to the space charge grid 71 through a resistor 85 of about 3900 ohms in series with an inductor 86 of about 150 microhenries. The negative-going potential excursions of the space charge grid 71 are restrained by a diode 89 having its cathode connected with the space charge grid 71 and its anode fed from the positive supply bus 90.

Continuous wave signal energy, which may have a frequency of about 11.25 megacyles may be applied from any suitable source to an input terminal 91 coupled through a resistor 92 of about 100 ohms to the outer control grid 93 of the tube 72. The internal impedance of the source feeding the terminal 91 provides a grid return for the grid 93 and permits the maintenance of the desired operating bias thereon.

The anode 95 of the tube 72 may be connected through inductor 96 shunted by resistor 97 of about 1000 ohms, with the positive supply bus 130. Direct current level signals may be derived from the anode circuit of tube 72 from the tap 98 running directly to the anode 95, while continuous wave packets are fed along another conductor 100 through coupling capacitor 99. A variable inductor 101 may be bridged between anode 95 and outer control grid 93 in series with a blocking capacitor 102, affording a means of eliminating electrostatic transfer of energy between the grid 93 and the set anode 9'5. In practice the value of the inductor 101 may be varied to minimize 'such electrostatic transfer.

In analyzing the operation of the illustrated circuit, it would be helpful to tirst `assume that no input signals are delivered to the control grid 13 of the normally conductive tube 14. Under these conditions, the anode 21 is clamped at approximately lS-volt negative level. Let it be further assumed that the tube 72 is conductive, while the tube 52 is nonconductive. Under these conditions, the space charge electrode 71 is clamped at a potential of approximately 90 volts positive with the result, that the step down networks 70, 75 acting in conjunction with resistors 54 and 59, respectively, apply a substantial negative potential to the grids 51 and 55 of the tube 52, to maintain this tube in a nonconductive state. The amplitude of the positive-going exciting pulse delivered through the diode 61 is insufficient to overcome this bias on the tube 52, whereby the tube combination 72, 52, remains in the assumed state of conduction and nonconduction. Negative pulses transmitted through the diodes 37 and 35 to the control grid 51 also do not disturb this state. Y

If, on the other hand, it be assumed that the tube 52 is conductive, while the tube 72 is nonconductive, the grids 51 and 55 are slightly positive with respect to the clamped potential of the anode 21 in the tube 14. With the arrival of the next positiveand negative-going impulses at terminals 64 and 39, respectively, a positivegoing signal is applied to the control grid 55 of the already conductive tube 52. Because of grid current, the positive-going signal does not subtantially change the potential of the said grid and is without inuence on the low of current through the tube 52. However, the negative-going impulse delivered to the anode of the diode 37 decreases the tiow of current through the resistor 34, permitting the junction point 36 to swing negatively to the clamped level of l5 volts, and initiate conduction through the diode 35 to deliver a negative-going impulse to the control grid 51 of the tube 52. This decreases the ilow of current to the anode 57, resulting in an increase in anode potential which is transmitted through the coupling network 81 to the first control grid 76 of the tube 72, initiating 4a flipping action by virtue of the back coupling between the space charge grid 71 of the tube 72 and the grids 51 land 55 of the tube 52. t

Therefore, with the tube 14 in the conductive state, the conduction pattern existing in the tubes 52, 72 is unaltered until the advent of a sharp timing pulse, which changes the state of the flip-op combination to one in which the tube 52 is conductive and the tube 72 is nonconductive, it' it has previously been in its other stable state. If such state previously existed, it will not be disturbed.

Assume now that the control grid 13 of the tube 14 is driven negative to cut otf the ow of current therethrough, whereupon the potential of the anode 21 rises to about ground level. With the tubes 52, 72 in the state shown in the drawing, namely tube 52 nonconductive and tube 72 conductive, there is no immediate effect because of the overriding action of the strongly negative bias on the rst control grid 55 of the tube 52, which prevents the flow of current to the anode S7 despite the less negative bias on the control grid 51 of thetube 52. However, upon the receipt of the next positive-going impulse of the terminal 64, independently of the simultaneously appearing negative-going impulse of the terminal 39, the voltage of the control grid 55 is driven into the conductive region, initiating the flow of current to the anode 57 to trigger the tube combination 52, 72 to a state in which the tube 52 is conductive and the tube 72 is nonconductive. Interference by the negative-going impulse of the terminal 39 is prevented by the clamping action of diodes 31, 32, which prevent the junction 50 from becoming appreciably negative with respect to ground under the assumed condition of nonconduction in the tube 14.

Assuming now that the tube 52 is conductive and the tube 72 nonconductive, when the tube 14 is made nonconductive, .this` state is` found not to be disturbed by subsequently arriving impulses appearing at the terminals 39 and 64. This is because the junction point 50 will have been brought substantially to ground potential by the back coupling to the space charge electrode circuit of the tube 72 and is prevented from falling appreciably below this level despite the application of a negative-going impulse to the anode of the diode 37 by virtue of the clamping action of the diode 32 acting in conjunction with diode 31. The further application of positive-going impulses to the control grid 55 of the tube 52 through the diode 61 also does not disturb the assumed existing pattern of conduction in the tube and nonconduction in the tube 72.

The signals on the control grid 93 of the tube '72 are superimposed on the current owing to the anode 95 of the tube 72 whenever the inner electrode assembly permits the passage of such current. Accordingly, the input carrier wave present at the terminal 91 gives rise to a corresponding signal in the anode circuit of the tube 72 whenever the said tube is conductive; and as the tube is alternately rendered conductive and nonconductive, corresponding packets of cartier wave energy may be transmitted over the line 100. If essentially static signals are desired from the output of this device, the lead 98 is coupled through any suitable decoupling arrangement, such as a series resistor with the end remote from the anode 95 grounded for high frequency current through a capacitor, to the desired circuit to be served. The arrangement described operates equally Well with discrete pulse input and with pulse envelope input and has the property of converting individual pulse input into a pulse envelope system of notation standardized in time by the driving impulses supplied to the terminals 39 and 64.

While frequent reference has been made throughout to the particular vacuum tubes employed illustratively in `describing the invention, it may be understood that any other form of electric valve may be equally well employed in accordance with the principles of the invention. Such devices might include semi-conductors and magnetic amplifiers which are cited by way of example and not as limitations. Where diodes have been shown, it is to be understood that these may be of the thermionic type, the germanium crystal type, or selenium, or copper oxide plates depending upon the particular voltages, operating frequencies, circuit impedances, cost and the like.

Many other modifications and variations of the invention, not departing essentially from the spirit thereof, will be immediately apparent to those skilled in the art when faced with particular requirements by way of service conditions and environment.

What is claimed is:

1. ln signaling apparatus, a first electric valve having output electrodes and a control electrode, a second electric valve having a first output electrode under the inliuence of supervisory and auxiliary control electrodes and a second output electrode primarily under the iniiuence of said auxiliary control electrode, a connection between said iirst output electrode of said second valve and said control electrode of said first valve, a connection between an output electrode of said iirst valve and said supervisory control electrode of said second valve, a signal input line connected with said auxiliary control electrode of said second electric valve, and a signal output line connected with said second output electrode of said second electric valve.

2. In signaling apparatus, a rst electric valve having output electrodes and supervisory and auxiliary control electrodes, a second electric valve having output electrodes and a control electrode, a connection between an output electrode of said second valve and a control electrode of said first valve, a connection between an output electrode of said first valve and said control electrode of said second valve, a signal line conveying positive- 6 going electric impulses to one of the said control electrodes of said first electric valve, and a signal line conveying negative-going electric impulses to the other of said control electrodes of said rst electric valve.

3. In signaling apparatus, a iirst electric valve having output electrodes and supervisory and auxiliary control electrodes, a second electric valve having output electrodes and supervisory and auxiliary control electrodes, a connection between an output electrode of said second valve and a control electrode of said first valve, a connection between an output electrode of said rst valve and a control electrode of said second valve, a first signal line conveying positive-going electric impulses to one of said control electrodes of said rst electric valve, a second signal line conveying negative-going electric impulses to the other of said control electrodes of said first electric valve, a third signal line conveying periodic electric signals to one of said control electrodes of said second valve, and a signal output line connected with an output electrode of said second electric valve.

4. In signaling apparatus, a first electric valve having output electrodes and supervisory and auxiliary control electrodes, a second electric valve having output electrodes and supervisory and auxiliary control electrodes, a connection between an output electrode of said second valve and a control electrode of said irst Valve, a connection between an output electrode of said irst valve and a control electrode of said second valve, a rst signal line conveying positive-going electric impulses to said supervisory control electrode of said first electric valve, a second signal line conveying negativegoing electric impulses to said auxliliary electrode of said lirst electric valve, a third signal line conveying periodic electric signals to said auxiliary control electrode of said second valve, and a signal output line connected with an output electrode of one of said valves.

5. In signaling apparatus, a first electric valve having output electrodes and supervisory and auxiliary control electrodes, a second electric valve having output electrodes and supervisory and auxiliary control electrodes, connections between a first output electrode of said second Valve and said control electrodes of said iirst valve, a connection between an output electrode of said first valve and said supervisory control electrode of said second Valve, a rst signal line conveying positive-going electric impulses to said supervisory control electrode of said rst electric valve, a second signal line conveying negative-going electric impulses to said auxiliary electrode of said first electric valve, a third signal line connected with said auxiliary control electrode of said second Valve, and a signal output line connected with an output electrode of one of said valves.

6. ln combination, an electric valve having output electrodes and iirst and second control electrodes, a work circuit connected with one of said output electrodes, a iirst unilateral conductor linking said lirst control electrode with a first source of electric signals, second and third unilateral conductors connected in series with opposing polarity between said second control electrode and a second source of electric signals, a fourth unilateral conductor linking the junction between said second and third unilateral conductors with a third source of electric signals, and a iifth unilateral conductor linking said third source of electric signals with said second control electrode.

7. In combintion, an electric valve having output electrodes and first and second control elec'trodes,a work circuit connected with one of said output electrodes, a first unilateral conductor having its anode connected with a first source of electric signals and its lcathode connected with said iirst control electrode, second unilateral conductor having its anode connected with said second control electrode, third and fourth unilateral conductors having their cathodes connected with the cathode of said second unilateral conductor, a connection between the anode of said third unilateral conductor and a second source of electric signals, a connection between the anode of said Afourth unilateral conductor and a third source of electric signals, and a fifth unilateral conductor having its anode connected with said third source of electric signals and its cathode connected with said second control electrode.

8. In an apparatus for converting signal pulses into standardized enveloped signals, a iirst electric valve, a rst source of clock pulses and a transfer link connecting said first source to an input of said first valve, an input line connected to said transfer link carrying signals which prohibit the passage of pulses from said rst source, a second source of clock pulses connected to another input of said first valve, a second electric valve with its input connected to the output of said rst valve and its conductivity being conditioned by the nonconductivity of said rst valve, a source of carrier waves connected to another input of said second valve, and a signal output line connected to the output of said second valve.

9. The combination according to claim 8 wherein said transfer link comprises asymmetrical conductors.

10. The combination according to claim 8 wherein another output of said second valve is connected to an input of said rst valve.

References Cited in the tile of this patent UNITED STATES PATENTS 2,399,135 Miller et al. Apr. 23, 1946 2,405,597 Miller Aug. 13, 1946 2,478,683 Bliss Aug. 9, 1949 2,482,544 Jacobsen Sept. 20, 1949 2,519,763 Hoglund Aug. 22, 1950 

